Various types of compositions for controlling termites have been used for preventing the damage to wooden buildings and constructions caused by termites. Among those types of insecticidal compositions for controlling termites, organochlorine insecticidal compositions such as dieldrin, aldrin and chlordane, had been extensively utilized worldwide and initially admired. Those compositions, however, caused environmental contamination due to an increase in the overall use of the chemicals and their indecomposable characteristics, which are prohibited in their use presently in Japan by legislation as they are classified legally as specific harmful chemical substances.
There are a number of termite control compositions for pressure process, such as CCA (mixture agent containing copper, chrome and arsenic), CFK (mixture agent containing copper, chrome and fluorine) and CFK-Z (mixture agent containing copper, chrome, zinc and fluorine). These compositions are used for the combined effects in prevention of termites and wood rot fungi, and recently their consumptions have increased. Among those compositions, particularly in the case of CCA, disposal of the waste wood became a troublesome issue as the applications increased, for which some local authorities have banned its use. Some European countries prohibited the actual applications thereof even more than ten years ago.
Of late, use has been limited to the organophosphorus compounds, carbamate compounds and pyrethroid compounds in view of relatively low toxicity and low environmental pollution potential.
Phoxim, Chlorpyrifos and Fenitrothion and the like are examples of the organophosphorus compound. Bassa and Propoxur and the like are examples of carbamate compounds. Permethrin, Tralomethrin, Bifenthrin, Cyfluthrin and Deltamethrin and the like are pyrethroid compounds in actual use.
While the outstanding problems are rather less serious in the effectiveness of organophosphorus and carbamate compounds, the problem in causing inhibition of cholinesterase activity to the workers who handle the product is still remaining unsolved because their insecticidal activities are based on the inhibition of cholinesterase.
Although it is demanded that termiticidal agents retain their preventing action on target insects for long time, it is difficult to expect that the pyrethroid compounds would have sustained insecticidal activity against termites. The lack of its sustained insecticidal activity together with its demerit in higher cost versus performance available necessitates combining use with a inexpensive synergist.
However, there are still remaining issues such as unsatisfactory properties of such agents in view of application dosage, biological activity against termites, harmlessness to human beings, etc., less potential in environmental contaminations, and limitation of applications including application frequency, as well as extensive necessitiy of not only very quick termiticidal activity but also durable actions because of use for buildings or structures such as wooden houses and cultural treasures which are partially or totally constructed with wood. Therefore, it is still desirable to solve such issues.
Practically, there is a trend that use of agents has been minimized with their minimal concentration being determined with a view toward harmlessness to human beings, etc. and less potential environmental contamination. Furthermore, since, in consideration that the prevention or eradication of termites totally depends on the effectiveness of the chemical composition and the application technology available, reduction of its absolute volume requires more accuracy in the working arrangement and it tends to make the composition more vulnerable to deterioration in the application environment. Thus, more time is needed to further reduce the effective applied volumes of such compositions.
As explained above, the prior art has never been satisfactory in view that there are various issues pertaining to compositions for controlling or eradicating termites, such as activity of the composition, safety of the operator as well as the house owner, balance between its concentration in the actual application and cost or sustained activity of the insecticidal composition, and so on.